Distribution Of Bromine Research Articles

Halogens in pore water of peat bogs – the role of peat decomposition and dissolved organic matter

Abstract. Halogens are strongly enriched in peat and peatlands and such they are one of their largest active terrestrial reservoir. The enrichment of halogens in peat is mainly attributed to the formation of organohalogens and climatically controlled humification processes. However, little is known about release of halogens from the peat substrate and the distribution of halogens in the peat pore water. In this study we have investigated the distribution of chlorine, bromine and iodine in pore water of three pristine peat bogs located in the Magellanic Moorlands, southern Chile. Peat pore waters were collected using a sipping technique, which allows in situ sampling down to a depth greater than 6m. Halogens and halogen species in pore water were determined by ion-chromatography (IC) (chlorine) and IC-ICP-MS (bromine and iodine). Results show that halogen concentrations in pore water are 15–30 times higher than in rainwater. Mean concentrations of chlorine, bromine and iodine in pore water were 7–15 mg l−1, 56–123 μg l−1, and 10–20 μg l−1, which correspond to mean proportions of 10–15%, 1–2.3% and 0.5–2.2% of total concentrations in peat, respectively. Organobromine and organoiodine were the predominant species in pore waters, whereas chlorine in pore water was mostly chloride. Advection and diffusion of halogens were found to be generally low and halogen concentrations appear to reflect release from the peat substrate. Release of bromine and iodine from peat depend on the degree of peat degradation, whereas this relationship is weak for chlorine. Relatively higher release of bromine and iodine was observed in less degraded peat sections, where the release of dissolved organic carbon (DOC) was also the most intensive. It has been concluded that the release of halogenated dissolved organic matter (DOM) is the predominant mechanism of iodine and bromine release from peat.

Unprecedented μ3-Oi face-capping ligand in a [Mo6Bri6Li2Bra6] (L = 0.5 O + 0.5 Br) molybdenum cluster unit: crystal structure of the Cs3Mo6Br13O oxybromide

Abstract The new Cs3Mo6Br13O oxybromide, synthesized by solid-state chemistry, crystallizes in the trigonal system (R 3 _ c space group; a = 15.5784(2) A, c = 19.5103(5) A, V = 4100.5(1) A3 and Z = 6). It is based on a [Mo6L14] unit that contains an unprecedented μ3 face-capping oxygen. The crystal structure determined by single crystal X-ray diffraction is built up from discrete face-capped [Mo6Bri6Li2Bra6]3– (L = 0.5 O + 0.5 Br) anionic units in which two inner positions are randomly occupied by one bromine and one oxygen whereas the other ligand positions are fully occupied by bromine. The cesium cations randomly occupy two close crystallographic positions generated by the A-B-C-A′-B′-C′ close-packed stacking of the units. The cesium site occupancy is related to the random distribution of oxygen and bromine on the Li inner positions. To cite this article: K. Kirakci et al., C. R. Chimie 8 (2005).

The Thermal Degradation Process of Tetrabromobisphenol A

This study focused on the investigation of the thermal degradation process of tetrabromobisphenol A (TBBA). The use of combined experimental techniques allowed the quantitative characterization of TBBA decomposition products and the analysis of the thermal degradation rates. The distribution of bromine among the different decomposition product fractions was investigated. In the open configuration used for the experiments, hydrogen bromide, brominated bisphenol A species, and brominated phenols resulted in the main decomposition products. Bromine was mainly evolved as hydrogen bromide, although a relevant quantity resulted present in the primary high molecular weight condensable product fraction, in agreement with the decomposition pathways proposed. The results evidenced that accidents involving TBBA thermal degradation, such as fire or process runaways, may pose relevant safety problems because of the possible release of considerable quantities of hazardous decomposition products.

Non-polar halogenated natural products bioaccumulated in marine samples. II. Brominated and mixed halogenated compounds

Several identified and potential natural brominated bioaccumulative compounds were studied in this work. 4,6-dibromo-2-(2 ′,4 ′-dibromo)phenoxyanisole (BC-2) previously detected in Australian marine mammals and isolated from sponges, was synthesized. Two byproducts (a tetrabromo isomer and a tribromo congener) were investigated as well. The byproducts of the synthesis were not identified in the environmental samples investigated. Previously described natural brominated compounds (BC-1, BC-2, BC-3, BC-10, BC-11, MHC-1) and anthropogenic brominated diphenyl ethers (BDE-47, BDE-99, BDE-100, BDE-154) were detected in a sample of human milk. The sample was from a woman from the Faeroe Islands who frequently consumed fish as well as whale blubber and meat. The most abundant compound originated from the natural tetrabromo phenoxyanisole BC-3 which may have a 3:1 distribution of bromine on the two phenyl units. This sample also accumulated a dibromochloroanisole, as well as a previously unknown mixed halogenated compound (MHC-X) and an unknown, most likely aromatic brominated compound. Co-elutions on a DB-5 column were found for BDE-99 and BC-11 as well as BDE-154 and the unknown brominated compound. This suggests that quantification of these two compounds has to be carried out carefully. Two samples of lower trophic level, namely Baltic cod liver and Mexican mussel tissue, were investigated as well. The cod liver samples contained BDE congeners but also abundant signals for the natural 2,3,3 ′,4,4 ′,5,5 ′-heptachloro-1 ′-methyl-1,2 ′-bipyrrole Q1 and tribromoanisole (TBA). The mussel sample contained Q1, TBA, another halogenated anisole, BC-1, BC-2, and BC-3, as well as additional, potential natural brominated compounds in the elution range of tribromophenoxyanisoles.

Inhomogeneous substitution of polyhalogenated copper-phthalocyanine studied by high-resolution imaging and electron crystallography

The present study was aimed at distinguishing halogen atoms substituted in a molecule of copper-phthalocyanine (CuPc) by high-resolution transmission electron microscopy (HRTEM). The subject was carried out on octabromooctachloro-CuPc and obtained HRTEM images suggested inhomogeneous distribution of bromine and chlorine atoms at 1-, 2-, 3- and 4-substitution positions of CuPc in image contrast. As a result of electron crystallography, the occupancy of bromine atoms at the 1-position (and equally at the 4-position) was found to be 52%, which is slightly higher than for random substitution. This small deviation causes apparent inhomogeneous image contrast of halogen substitution observed in the high-resolution images, as concluded from computer simulation of images. Such potential to detect inhomogeneity in substitution by TEM should be important for the chemical understanding of substitution reactions at the atomic level.

Bromine content of English Zechstein Cycle 3 chloride salts on Teesside and in the Staithes area of Co. Cleveland, N.E. England

SUMMARY We present profiles of the vertical distribution of bromine in cores of the late Permian (Zechstein) Boulby Halite Formation (EZ3 Na) from lower Teesside and from the potash field around Boulby Mine, Staithes, North Yorkshire. The profile for the Teesside core shows that the bromine content of the halite there (and therefore the salinity of the originating brine) lies in the lower part of the range regarded as normal for marine-derived brines throughout deposition of the formation and increases only slightly near the top. The bromine content of the Boulby Halite in the potash field core is generally slightly greater than that in the Teesside core, but, as predicted by conventional theory, increases sharply in the Boulby Potash Member near the top of the formation. Comparison of the two bromine concentration profiles suggests a close correlation. This suggested correlation needs to be tested against other bromine profiles but, if correct, implies (a) that closely sampled bromine profiles are a useful tool in the correlation of salt deposits, and (b) the Boulby Potash is entirely, or almost entirely, younger than the Boulby Halite of Teesside, possibly indicating basin-shrinkage.

Fluctuations in Fe, Cu, Zn, Br, As, Se, and Rb concentrations in C57L/J mice bearing BW7756 murine hepatoma using radioisotope-induced X-ray fluorescence

The effects of selenite or selenate supplementation on the concentration and distribution of Fe, Cu, Zn, As, Br, and Rb are investigated using the radioisotope-induced X-ray fluorescence, RIXRF. These effects are studied in the animals bearing BW7756 murine hepatoma and healthy animals for both of the oxidation states. Selenite and selenate induce different effects on the distribution of selenium, zinc, copper, bromine, and rubidium. The differences may be attributed to the differences in the inter element interaction after absorption into the bloodstream as well as to the mode of their intestinal absorption. Simultaneous supplementation of copper with selenite or selenate at the described levels has a profound influence on the concentration levels of other elements in the normal as well as in the diseased mice. The administration of selenium (0.67 micrograms/g body wt sodium selenite or sodium selenate, daily) and selenium and copper (0.67 and 1.35 micrograms/g body wt, respectively) has no effect on the incidence rate of hepatoma development.

Effects of thyroparathyroidectomy on the distribution of bromine and iodine in rat tissues.

The concentrations of iodine (I) and bromine (Br) were measured by inductively coupled plasma mass spectrometry in the plasma, kidney, heart, liver, and brain of control and thyroparathyroidectomized (TPTX) rats without and with an additional intake of either NaI or NaBr, 0.5 and 5 mumol/kg/d, respectively, for 21 d. In all groups, the highest concentrations of I and Br were found in the plasma. TPTX did not modify the concentrations of I in tissues, but slightly increased Br in plasma (+33%) and kidney (+24%). The additional intake of I with the drink induced an increase of I concentrations in the tissues tested (from 54 to 191%), except brain, both in control and TPTX rats. This additional intake of I also increased Br levels in the plasma of control (+24%) and TPTX rats (+53%). The additional intake of Br with the drink induced an increase of Br levels in all the tested tissues, brain included (from 85 to 284%). The augmentation was higher in the tissues, particularly brain, of TPTX rats than of controls. The increase of Br in brain after an additional intake contrasts with the absence of increase of I given in the same conditions. This difference between I and Br probably results from the smaller radius of Br ion in comparison with I ion radius. In conclusion, TPTX did not modify the distribution of I in the tested tissues, but slightly increased the concentrations of Br in plasma and kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

Transbilayer distribution of bromine in fluid bilayers containing a specifically brominated analog of dioleoylphosphatidylcholine

We describe in this paper the transbilayer distribution of the bromines of the specifically halogenated phospholipid 1-oleoyl-2-(9,10-dibromostearoyl)-sn-glycero-3- phosphocholine (OBPC). The distribution was determined by X-ray diffraction of oriented multilayers of mixtures of OBPC and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) at 66% relative humidity by the general approach of Franks et al. (1978) [Nature 276, 530-532]. The bromine distribution of OBPC in the fluid L alpha phase is described accurately by a pair of Gaussian functions located 7.97 +/- 0.27 A from the center of the bilayer with l/e half-widths of 4.96 +/- 0.62 A. We find that OBPC bilayers are accurately described as DOPC bilayers with an additional bromine distribution centered at the position of the double bond of DOPC and conclude that OBPC is an excellent structural isomorph for DOPC under the conditions of these experiments. The distribution obtained is the complete and fully resolved transbilayer image of the halogen label because the broad distribution of the bromines is due entirely to thermal disorder and not to experimental limitations [Wiener, M. C., & White, S. H. (1991a) Biophys. J. 59, 162-173]. The observed width of the bromine distribution indicates that virtually all of the hydrocarbon interior is accessible to the bromines. The distance between the bromine/double-bond position and the headgroup phosphate position was determined from one-dimensional Patterson maps and found to be approximately 12 A. The application of accurately determined bromine distributions to the quantitative interpretation of fluorescence quenching experiments is discussed. A method for the self-consistent global analysis of diffraction data from mixtures that permits the use of data sets with different instrumental scale factors is developed in an Appendix.

Distribution of halomethanes in potable waters of Kuwait

The distribution of bromine containing trihalomethanes in the water distribution system of Kuwait has been studied. Total halomethanes in the drinking water averaged 25.6 ± 9.1 μg l −1 with a maximum of 50.5 μg l −1. Average concentrations (μg l −1) of individual compounds were: CHBr 3, 13.6 ± 4.6; CHBr 2Cl, 8.8 ± 3.7; CHCl 2Br, 3.3 ± 1.5. Water from roof top storage tanks contained significantly less halomethanes than that from underground reservoirs.

The behaviour of iodine and bromine in estuarine surface sediments

The distribution of iodine and bromine was examined in sediments which receive inputs of marine and terrigenous organic matter. The I and Br concentrations are directly related to the content of ‘marine’ organic matter defined using carbon/nitrogen ratios. In the Etive sediments both Br and I may be used as an indicator of ‘marine’ organic matter; Br is of general application as the Br C mar ratio (180 × 10 −4) is similar to ratios in other sedimentary environments but the use of I is restricted as the I C mar ratio is unlike those in other sediments. Experimental study of iodine sorption clearly shows the importance of decaying marine organic matter and oxygenated conditions in the incorporation of iodine by sediments. This suggests that the mechanism of incorporation of iodine by seston previously proposed is probably an important pathway to sediments. The similarity of Br association with marine organic matter suggests that Br sorption as opposed to residual enrichment may be important for sediment Br accumulation.

Polarized X-Ray Absorption Spectra of Bromine-Doped Polyacetylene; Evidence for Highly-Oriented Polybromine Ions

Polarized extended X-ray absorption fine structure (EXAFS) and near-edge spectra are measured on the Br K-edge for streteh-oriented trans -(CHBr y ) x . A large difference is observed in both the EXAFS and near-edge regions between the spectra with the polarization vector E parallel and perpendicular to the axis of orientation. The Fourier transform results or polarized EXAFS demonstrate that polybromine ions are highly oriented along the fibril axis in the dopant concentration 0.015 < y < 0.036. Bromines are also shown to be covalently bonded with carbon atoms of the polymer backbone through a substitution reaction and dominate the radial distribution of bromine in the direction perpendicular to the fibril axis. Polarized near-edge spectra show that the anisotropic bonding states of bromine are characterized by the Br-Br bond in the parallel direction and the Br-C bond in the perpendicular direction to the fibril axis, respectively. We propose that trans -(CHBr y ) x can be described in terms of highly o...

La chimie du plomb et du brome particulaire en atmosphere urbaine: II — [formula omitted

In an abnormal urban atmospheric situation, where we have detected an exceptional increasing of lead concentration which could have no relation to traffic modification, we have been able to detect others sources, that has been possible thanks to simultaneous studies of granulometric distribution and concentrations of lead and bromine in this particular atmosphere.

Distribution of Methyl Bromide and Bromine in Rats, and Their Biochemical Indicators

Distribution of Methyl Bromide and Bromine in Rats, and Their Biochemical Indicators

The distribution of bromine in coastal sediments and its use as a source indicator for organic matter

The distribution of bromine associated with sedimentary organic matter (SOM) was examined in the Gulf of Maine and two contiguous estuaries. The bromine to organic carbon (Br:OC) ratio is constant throughout the Gulf of Maine but shows considerable variability in the estuarine regions. These variations seem to reflect the bromine contents of the various primary productivity sources of the SOM. Decreasing Br:OC ratios correlate with decreasing δ 13C values in a suite of estaurine sediments containing varying proportions of marine-derived and terrigenous SOM. High Br:OC ratios appear to represent macroalgal contributions to SOM. While both Br and OC levels are dependent upon sediment texture, their ratio is not. Br:OC ratios in SOM are higher than those of its primary productivity sources, which may result from residual enrichment of brominated organic material during decay rather than uptake of Br − by SOM.

Total body electrolyte composition and distribution of body water in uremia

Total body sodium and chloride were measured by neutron activation analysis, and total body potassium was measured by whole body counting in ten male patients with endstage renal disease requiring chronic maintenance hemodialysis. The extracellular fluid volume was estimated from the simultaneously measured volume of distribution of bromine 77 and sodium 24. Total body water was estimated from the volume of distribution of triated water. Total body sodium and chloride were significantly increased above normal measured values, but total body potassium was not significantly different from normal. The increase in total body sodium could be attributed to an increase in exchangeable sodium because no significant change in the nonexchangeable portion of total body sodium could be detected. Extracellular fluid volume, estimated fro three different techniques (total body chloride, sodium 24, and bromine 77), and total body water were increased significantly above normal values. Extracellular fluid volume was correlated with exchangeable sodium, and total body water was closely correlated with total cation content (exchangeable sodium and total body potassium). The calculated intracellular fluid volume was decreased and was closely correlated with total body potassium. Despite adequate control of uremia by chronic maintenance hemodijalysis, body electrolyte composition and the distribution of body water remain significantly different from normal.

The contrasting geochemical behaviours of iodine and bromine in recent sediments from the Namibian shelf

The vertical distribution of iodine, bromine and organic carbon has been examined in sediment cores from a range of environments on the Namibian shelf. The relationship between Br and C org. is linear, and that between I and C org. is variable, for all surface sediments; I/C org. ratios show a decrease of about one order of magnitude between the outer shelf oxidising sediments ( 250 × 10 −4 ) and the organic-rich inner shelf sediments ( 20 × 10 −4 ). The contrasting behaviour of the halogens in surface sediments is explained by differences in the amount of halogen absorbed by living organisms within the euphotic zone and on seston on the seabed. It is suggested that sorption by seston occurs only in oxidising sediment where free O 2 is available. Hence, iodine is sorbed by seston in the outer shelf environment, but is not sorbed by the reducing sediments of the inner shelf. Here the iodine in the sediment represents only that taken up by plankton. On the outer shelf, 50–80% of the total iodine in the organic matter is sorbed by seston. The principal site of Br uptake is not known. The distribution of C org. in subsurface sediments broadly reflects that found at the surface, although there is a slight decrease with depth in the outer shelf cores due to dilution by terrigenous materials. In the inner shelf cores, there is no change in the relationship of iodine and bromine to organic carbon at depth. Those from the mid shelf, and especially the outer shelf, on the other hand, show decreases in both I/C org. and Br/C org. ratios, reaching values at about 70 cm depth that are similar to those in surface reduced sediments from the inner shelf. Over this depth interval I/C org. ratios decrease by a factor of five while Br/C org. ratios show a two fold decrease. These changes in the ratios at depth imply that diagenesis within the reducing cores is negligible compared with that of oxidised sediments. The implications of diagenesis with regard to halogen recycling in sediments are briefly discussed.

Regional distribution of halogens in Norwegian forest soils

Regional distribution of chlorine, bromine, and iodine in humus layers of Norwegian forest soils has been studied by means of neutron activation analysis. The halogen concentrations show a rapid decrease at increasing distances from the ocean, indicating that the supply of these elements to the soil is mainly through precipitation. Strong correlations between Cl and exchangeable Na + and Mg 2+, indicate atmospheric input to soils for these two cations as well.

The global distribution of iodine, bromine, and chlorine in marine aerosols

Atmospheric samples have been analyzed for iodine, bromine, and chlorine by neutron activation analysis. Aerosols of marine origin, derived from sea spray, are found to contain the halogens in relative proportions different from sea water, and data from Hawaii and winter northern Alaska indicate fractionation of the elements both during transfer across the sea-air interface and by chemical reactions in the atmosphere. The ratio Br/Cl is usually severalfold greater in aerosols over land than in sea water (Br/Cl=0.0034), but over open sea water it is less. In general, the ratio I/Br exhibits a greater degree of constancy (values cluster in the region I/Br ∼ 0.1–0.2) than does either I/Cl or Br/Cl, suggesting a long residence time and a coherence of I and Br in their movement as particulate material in the atmosphere. However, a singularly effective sea-air transfer mechanism for iodine is indicated by its generally high atmospheric concentration compared to sea water (I/Br=0.001). Bromine of pollution origin and associated with lead has been observed in aerosols from Cambridge, Massachusetts. Chlorine and iodine concentrations are similar to the Hawaii values and provide a basis for resolving excess pollution bromine from the natural marine component. The ratio (excess Br)/Pb in aerosols appears to be correlated directly with the haziness of the air.

Chemical Kinetics of Bromine Following Neutron Capture

The kinetic behavior of Br80 produced by neutron capture has been investigated in gaseous systems containing ethyl bromide, ethylene and hydrogen bromide. The distribution of active bromine between organic and inorganic form has been shown to be principally dependent on the ethylene pressure. A kinetic scheme, incorporating a ``hot atom'' reaction, is postulated and shown to be in agreement with the experimental facts. Additional experimental tests of critical points in the proposed scheme have been successful.